A line head type inkjet recording apparatus is used in many fields because of its capability of high-speed continuous recording of designs or letters based on predetermined image data.
In recent years, in addition to four colored inks of yellow (Y), magenta (M), cyan (C), and black (K) (called “YMCK”), such an inkjet recording apparatus simultaneously provides value-added special inks, such as an ink having an intermediate color between these colors, a fluorescent color ink or an ink having a weather-resistant agent.
In addition, accordingly, many inkjet recording apparatuses having an increased number of line heads have been developed.
By the way, in an inkjet recording apparatus, generally, the frequencies of respective inks to be used are different largely according to image data. Therefore, for example, an unused special ink might dry and solidify in a nozzle portion of a line head while inkjet recording is being performed using other inks. Then, the nozzle portion clogs up, and it takes time to clear the clogged nozzle.
On the other hand, in order to suppress drying of an ink, for example, such a method is used as temporarily detaching a line head containing an unused ink or moving the same so as to wait in another position.
However, the positions of the nozzles of the line heads need to be finely aligned with a micron unit, and therefore, once the line head is moved, there is the disadvantage that it becomes difficult to perform pitch alignment when the line head is put back to its original position.
It should be noted that as an inkjet recording apparatus capable of preventing the drying of an unused ink, there is a known inkjet recording apparatus including a black print head, a color print head, a black print head cap to close a nozzle of the black print head, a color print head cap formed as a separate member from the black print head cap and closing a nozzle of the color print head, a black cap moving means for moving the black print head cap between a closing position where the nozzle of the black print head is closed and a retracting position where the nozzle is opened, and a color cap moving means for moving the color print head cap between a closing position where the nozzle of the color print head is closed and a retracting position where the nozzle is opened (for example, see the patent literature 1). According to such an inkjet recording apparatus, by capping a nozzle of an unused color print head during ejection of a black ink to perform printing, an ink in the nozzle can be prevented from drying.